983
FXUS63 KBIS 171238
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
638 AM CST WED DEC 17 2025
KEY MESSAGES
- A HIGH-END WIND EVENT IS EXPECTED ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THIS AFTERNOON THROUGH THURSDAY MORNING, WITH
WIDESPREAD MAXIMUM GUSTS RANGING FROM AROUND 60 MPH IN THE
TURTLE MOUNTAINS AREA TO AS HIGH AS 75 MPH IN THE SOUTHWEST.
- A PERIOD OF ACCUMULATING SNOW IS EXPECTED WITH THE VERY STRONG
WINDS LATE THIS EVENING INTO THURSDAY MORNING, WITH FORECAST
TOTALS RANGING FROM AROUND ONE HALF INCH ALONG THE SOUTH
DAKOTA BORDER TO AROUND 2 TO 4 INCHES IN FAR NORTHWEST AND
NORTH CENTRAL NORTH DAKOTA.
- THE VERY STRONG WINDS COMBINED WITH THE SNOW MAY PRODUCE
BLIZZARD CONDITIONS ACROSS NORTHERN AND EASTERN PARTS OF THE
STATE, AND A SHORTER-DURATION PERIOD OF DANGEROUS WHITEOUT
CONDITIONS (SNOW SQUALLS) IN THE WEST AND SOUTH CENTRAL.
UPDATE
ISSUED AT 638 AM CST WED DEC 17 2025
THE NEAR-TERM FORECAST REMAINS ON TRACK. CURRENT CONDITIONS AND
TRENDS WERE BLENDED IN FOR THIS UPDATE.
DISCUSSION
ISSUED AT 513 AM CST WED DEC 17 2025
A WELL-ADVERTISED POWERFUL ALBERTA CLIPPER WITH FORECAST
MINIMUM MSLP AS LOW AS 980 MB WILL IMPACT THE NORTHERN PLAINS
THIS AFTERNOON THROUGH THURSDAY. ALREADY VERY HIGH CONFIDENCE
CONTINUES TO INCREASE THAT THIS WILL BE A HIGH-IMPACT EVENT FOR
OUR FORECAST AREA, WITH WHITEOUT CONDITIONS AND VERY INTENSE
WIND GUSTS. THE HIGHEST PROBABILITIES FOR BLIZZARD CONDITIONS
(AT LEAST 3 HOURS OF 1/4 MILE VISIBILITY) ARE GENERALLY ALONG
AND TO THE NORTH AND EAST OF HIGHWAY 52, WHILE THE POTENTIAL FOR
EXTREME WIND GUSTS INCREASES TO THE SOUTH AND WEST.
LITTLE TO NO NOTABLE WEATHER IS ANTICIPATED UNTIL EARLY THIS
AFTERNOON, ALTHOUGH BROAD MID LEVEL WARM AIR ADVECTION COULD
PRODUCE SOME VERY LIGHT "FREEZING SPRINKLES" FALLING THROUGH A
WARM AND DRY LAYER ALOFT THIS MORNING. MEASURABLE PRECIPITATION
IS NOT ANTICIPATED FROM THIS. EARLY THIS AFTERNOON, AN INITIAL
SURGE OF COLD AIR ADVECTION WITH STRONG PRESSURE RISES IS
FORECAST TO PUNCH INTO WESTERN NORTH DAKOTA, PRECEDED BY AN AREA
OF RAIN SHOWERS. NORTH CENTRAL PARTS OF THE STATE ARE LESS
LIKELY TO FEEL THE BRUNT OF THIS INITIAL BURST OF WINDS, BUT
THERE IS POTENTIAL FOR MIXED PRECIPITATION IN THE TURTLE
MOUNTAINS AREA LATE THIS AFTERNOON AND EVENING, WHICH MAY
INCLUDE FREEZING RAIN PRODUCING A LIGHT GLAZE OF ICE
ACCUMULATION. BACK TO THE SOUTH AND WEST, TEMPERATURES SHOULD
REMAIN ABOVE FREEZING DURING THE INITIAL PERIOD OF HIGH WINDS,
WHICH FORECAST SOUNDINGS INDICATE COULD BE AS HIGH AS 55 TO 65
MPH. THIS PERIOD OF STRONGER GUSTS IS LIKELY TO BE SHORTER-LIVED
AND LESS IMPACTFUL THAN WHAT IS TO COME.
MOST ENSEMBLE GUIDANCE HAS CONSOLIDATED ON A DOUBLE-BARREL
SURFACE LOW CROSSING SOUTHERN SASKATCHEWAN THROUGH THE NORTHERN
RED RIVER VALLEY, WHICH IS A SLIGHT NORTHWARD SHIFT FROM WHAT A
COUPLE OF GLOBAL ENSEMBLE CLUSTERS HAD BEEN SUGGESTING. EVEN IF
THE LOW DOES END UP TAKING A SLIGHTLY MORE SOUTHWARD PATH, WHICH
THERE ARE LOW PROBABILITIES FOR, THAT WOULD NOT CHANGE THE
EXPECTED IMPACTS AND MAGNITUDE THEREOF. ALL LOCATIONS WILL SEE A
PERIOD OF VERY INTENSE WINDS (EVEN BY NORTH DAKOTA STANDARDS)
AS THE ARCTIC COLD FRONT PLOWS THROUGH LATE THIS EVENING INTO
EARLY THURSDAY MORNING. THE ONLY MISSING INGREDIENT FOR A HIGH-
IMPACT WIND EVENT IS THE NOCTURNAL TIMING, BUT THIS SHOULD BE
COMPENSATED BY ALL OTHER INGREDIENTS BEING OBJECTIVELY OR
SUBJECTIVELY NEAR OR AT CLIMATOLOGICAL MAXIMA. DETERMINISTIC
MODELS PROJECT 3-HOUR PRESSURE RISES ON THE ORDER OF 15-20 MB
WITH STEEP LOW LEVEL LAPSE RATES DESPITE THE TIME OF DAY. MODEL
SOUNDING ANALYSES IN BUFKIT ALSO SHOWS VERY STRONG DOWNWARD
MOMENTUM TRANSFER OF MEAN MIXING LAYER WINDS THAT ARE FORECAST
TO BE AT LEAST AS STRONG AS 50-65 KTS. A WIND GUST EFI AT THE
MAXIMUM VALUE OF 1 WITH A SHIFT-OF-TAILS GREATER THAN 2 OVER
WESTERN NORTH DAKOTA ALSO IMPLIES HIGH CONFIDENCE IN A HIGH-
IMPACT EVENT.
WE HAVE HIGH CONFIDENCE THAT WINDS WILL BE STRONGEST IN THE
SOUTHWEST AND RELATIVELY "WEAKEST" IN THE TURTLE MOUNTAINS AREA,
ALTHOUGH GUSTS TO AROUND 60 MPH ARE STILL ANTICIPATED THERE.
THE TIMING AND DURATION OF THE STRONGEST WINDS WILL VARY BY
LOCATION, BUT CAN GENERALLY BE SUMMARIZED AS MID EVENING TO MID
THURSDAY MORNING WEST; LATE EVENING TO EARLY THURSDAY AFTERNOON
SOUTH CENTRAL; AND LATE TONIGHT TO LATE THURSDAY MORNING NORTH
CENTRAL.
THERE ARE SOME CONCERNING SIGNALS EMERGING IN RAPID-REFRESH
GUIDANCE THAT NEED TO BE ADDRESSED, BUT WE EMPHASIZE THESE ARE
STILL LOW-PROBABILITY OUTCOMES. HRRR/RAP SOUNDINGS AT BOWMAN
HAVE BEEN CONSISTENTLY SHOWING THE TOP OF THE MIXED LAYER TO
CONTAIN WINDS AS HIGH AS 100 KTS (115 MPH), AND THE MIDWAY POINT
OF THE MIXED LAYER EASILY HAS WINDS IN THE 70-80 KT (80-90 MPH)
RANGE. THIS OCCURS WHEN ALL THE AFOREMENTIONED INGREDIENTS FOR
MAXIMUM MOMENTUM TRANSFER POTENTIAL ARE FORECAST TO BE PRESENT,
ALONG WITH MEDIUM TO HIGH PRECIPITATION CHANCES (MORE ON THAT
BELOW). OTHER DETERMINISTIC MODEL SOUNDINGS ARE NOT THAT
EXTREME, BUT STILL SHOW AROUND 75-85 KTS AT THE TOP OF THE MIXED
LAYER AND AROUND 65-75 KTS AT THE MIDWAY POINT. WE CANNOT
RECALL SEEING A WIND SIGNAL LIKE THIS SINCE THE JANUARY 2021
WIND EVENT THAT PRODUCED ISOLATED GUSTS AS HIGH AS 90 MPH. THE
100 KTS MIXING DOWN TO THE SURFACE WOULD BE A WORST-CASE
SCENARIO AND IS BORDERLINE UNREASONABLE (BUT NOT IMPOSSIBLE).
BUT GIVEN THE LOWEST MIXING POTENTIAL IN THE SOUTHWEST SEEMS TO
BE AT LEAST AS HIGH AS 65 KTS, WE ARE ADVERTISING A REASONABLE
HIGH-END OUTCOME OF WIDESPREAD MAXIMUM GUSTS TO AROUND 75 MPH IN
SOUTHWEST NORTH DAKOTA. WE ANTICIPATE THERE WILL A FEW SPORADIC
GUSTS IN THE 80 TO 90 MPH RANGE, AND IT WOULD NOT BE SHOCKING
TO SEE A HIGHER TERRAIN LOCATION OR TWO (SUCH AS ON TOP OF A
BUTTE) TO RECORD A TRIPLE DIGIT WIND GUST. EVEN WITH THE MORE
CONSERVATIVE WIND GUST OUTCOME, THE STRENGTH OF THESE WINDS WILL
BE SIMILAR TO THOSE COMMONLY FOUND IN SEVERE THUNDERSTORMS
DURING THE SUMMER, AND CAN BE EXPECTED TO CAUSE AT LEAST MINOR
PROPERTY DAMAGE.
IF THE INTENSE WINDS WERE NOT ENOUGH, THEY ARE EXPECTED TO BE
ACCOMPANIED BY ACCUMULATING SNOW. THERE ARE HIGH PROBABILITIES
FOR AT LEAST 2 INCHES OF SNOW ALONG AND NORTH OF A LINE FROM
CROSBY TO MINOT TO DEVILS LAKE, AND LOW TO MEDIUM PROBABILITIES
FOR EXCEEDING ONE INCH REACH AS FAR SOUTH AS THE SOUTH DAKOTA
BORDER. LATEST MODEL/ENSEMBLE GUIDANCE HAS SLIGHTLY INCREASED
AMOUNTS/THRESHOLD PROBABILITIES FROM PREVIOUS FORECASTS AT MOST
LOCATIONS.
PRIOR TO THE ARRIVAL OF THE ARCTIC COLD FRONT AND NEW SNOWFALL,
WHATEVER IS LEFT OF SNOW ALREADY ON THE GROUND SHOULD NOT BE
BLOWABLE (NOTE: WIND GUSTS AS HIGH AS +70 MPH HAVE BEEN KNOWN TO
BREAK THROUGH CRUSTED SNOW PACKS, BUT SNOW MAY BE NEARLY, IF
NOT COMPLETELY MELTED IN AREAS WITH THE HIGHEST POTENTIAL FOR
GUSTS THAT STRONG). WHATEVER SNOW DOES FALL IN THE STRONG WINDS
IS CERTAIN TO PRODUCE WHITEOUT/BLIZZARD CONDITIONS, BUT THERE IS
STILL SOME UNCERTAINTY ON THE DURATION AND INTENSITY OF
BLIZZARD CONDITIONS EVEN WHERE FORECAST SNOW AMOUNTS ARE
HIGHEST. WITH THE INCREASE IN FORECAST SNOW AMOUNTS, WE HAVE
OPTED TO EXPAND THE WINTER STORM WATCH FOR BLIZZARD CONDITIONS
SOUTHWESTWARD INTO DIVIDE, MOUNTRAIL, SHERIDAN, WELLS, FOSTER,
AND STUTSMAN COUNTIES, AND MAINTAIN THE PRE- EXISTING WATCH AS
IS. ALL COUNTIES NOT UNDER A WINTER STORM WATCH HAVE BEEN
UPGRADED TO A HIGH WIND WARNING.
COUNTIES THAT ARE UNDER A HIGH WIND WARNING WILL NOT REMAIN
VOID OF HAZARDOUS WINTER WEATHER. IN FACT, WE HAVE MEDIUM TO
HIGH CONFIDENCE THAT THE ARCTIC COLD FRONT WILL PRODUCE SNOW
SQUALLS THAT MEET SNOW SQUALL WARNING CRITERIA. VIRTUALLY ALL
KNOWN RESEARCHED INGREDIENTS THAT SUPPORT SNOW SQUALL FORMATION
AND MAINTENANCE ARE FORECAST TO BE PRESENT, INCLUDING ALL
PREVIOUSLY MENTIONED INGREDIENTS FOR HIGH WINDS, A STRONG 0-1 KM
THETA-E GRADIENT, STRONG LOW LEVEL FRONTOGENESIS, SBCAPE AS
HIGH AS 100 J/KG, AND A SNOW SQUALL PARAMETER AS HIGH AS 10
(VALUES OF JUST ONE ARE SUFFICIENT)! THIS PHENOMENON WOULD
LIKELY ONLY LAST FOR AN HOUR AT MOST AT ANY GIVEN LOCATION. BUT
THE COMBINATION OF THE INTENSE WINDS WITH THE BURST OF SNOW
COULD CREATE AN EXTREMELY HAZARDOUS TRAVEL SITUATION. WE CANNOT
OVERSTATE THE DANGER OF BEING CAUGHT ON RURAL HIGHWAYS IN SNOW
SQUALLS, AS VISIBILITY CAN GO FROM "AS FAR AS THE EYE CAN SEE"
TO ZERO IN A MATTER OF SECONDS. THE HIGHEST SNOW SQUALL
POTENTIAL IS ACROSS WESTERN AND SOUTH CENTRAL NORTH DAKOTA THIS
EVENING THROUGH TONIGHT. THIS INCLUDES HIGHWAY 85 FROM WILLISTON
TO THE SOUTH DAKOTA BORDER, AND INTERSTATE 94 FROM THE MONTANA
BORDER TO BISMARCK. IT IS CRUCIAL THAT TRAVELERS IN THIS PART OF
THE STATE REMAIN WEATHER AWARE THIS EVENING AND TONIGHT, AND
STRONG CONSIDER ALTERING THEIR TRAVEL PLANS.
TEMPERATURES WILL PLUMMET BEHIND THE ARCTIC FRONT, WITH
WIDESPREAD WIND CHILLS IN THE 20S BELOW. A COLD WEATHER ADVISORY
MAY BE NEEDED FOR FAR NORTHERN PARTS OF THE STATE, WHERE WIND
CHILLS COULD FALL AS LOW AS 35 BELOW. THE ARCTIC AIR MASS WILL
BE SHORT LIVED THOUGH AS YET ANOTHER BUT MUCH WEAKER CLIPPER
SYSTEM CROSSES THE REGION LATE THURSDAY THROUGH FRIDAY. THE NBM
SHOWS TEMPERATURES RISING ABOVE FREEZING ACROSS THE WESTERN HALF
OF THE STATE FRIDAY AFTERNOON, BUT THIS MAY BE PROCEEDED BY A
PERIOD OF LIGHT MIXED PRECIPITATION IN THE MORNING. GUIDANCE
FAVORS A DRIER PATTERN THIS WEEKEND LEADING UP TO CHRISTMAS, BUT
WITH FLUCTUATING TEMPERATURES FOR WHICH THERE REMAINS LARGE
ENSEMBLE SPREAD.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 638 AM CST WED DEC 17 2025
SIGNIFICANT AVIATION IMPACTS ARE EXPECTED ACROSS WESTERN AND
CENTRAL NORTH DAKOTA THROUGHOUT THE FORECAST PERIOD, ESPECIALLY
THIS EVENING THROUGH TONIGHT.
VFR CONDITIONS SHOULD PREVAIL THROUGH THIS AFTERNOON, ALTHOUGH
THERE COULD BE SOME BRIEF MVFR VISIBILITY RESTRICTIONS WITH A
BAND OF RAIN MOVING ACROSS THE STATE FROM WEST TO EAST.
SOUTHERLY WINDS WILL INCREASE AND TURN WESTERLY THROUGH THIS
AFTERNOON AND EVENING, BECOMING VERY STRONG IN WESTERN NORTH
DAKOTA BY LATE EVENING WITH +50 KT GUSTS. WIDESPREAD LOW LEVEL
WIND SHEAR IS ALSO FORECAST THROUGH THIS EVENING.
A VERY STRONG COLD FRONT WILL MOVE ACROSS THE STATE FROM
NORTHWEST TO SOUTHEAST THIS EVENING THROUGH TONIGHT, WITH
NORTHWEST WINDS AROUND 35 KTS AND GUSTS AS HIGH AS 55 KTS
(PERHAPS STRONGER IN SOUTHWEST NORTH DAKOTA). SNOW IS ALSO
EXPECTED WITH AND TRAILING THE FRONTAL PASSAGE, WHICH MAY
PRODUCE NEAR-WHITEOUT CONDITIONS AT TIMES.
BIS WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM NOON CST /11 AM MST/ TODAY TO 2 PM CST /1
PM MST/ THIS AFTERNOON FOR NDZ001-009-010-017-018-031>033-040-
041-043-044.
WINTER STORM WATCH FROM 6 PM CST THIS EVENING THROUGH THURSDAY
MORNING FOR NDZ001>005-010>013.
HIGH WIND WARNING FROM 2 PM CST /1 PM MST/ THIS AFTERNOON TO
NOON CST /11 AM MST/ THURSDAY FOR NDZ009-017-018-031>033-040-
041-043-044.
HIGH WIND WARNING FROM 5 PM CST /4 PM MST/ THIS AFTERNOON TO 3
PM CST /2 PM MST/ THURSDAY FOR NDZ019>021-034>036-042-045>048-
050-051.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY
AFTERNOON FOR NDZ022-023-025-037.
UPDATE...HOLLAN
DISCUSSION...HOLLAN
AVIATION...HOLLAN
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